Fracking starts at landmark Lancashire site

Fracking for shale gas has begun for the first time in the UK since it was linked with earthquakes in 2011.

Energy firm Cuadrilla confirmed the controversial process had started at its site in Little Plumpton, Lancashire after a legal challenge failed on Friday.

Protester Ginette Evans said there was a "mood of disappointment" but insisted the fight was "not over".

Cuadrilla insisted the process was safe and would be of "enormous" benefit.

The company's chief executive Francis Egan said: "These are the first exploration wells that will be tested... we have high hopes for them but we have to wait and see what comes out."

If successful, he said it would "lead to tens of thousands of jobs and could be a very significant contributor to the exchequer and... could also reduce emissions because it will be better than importing gas from far afield".

What is fracking?

Fracking is the process of drilling down into the earth before a high-pressure water mixture is directed at the rock to release the gas inside.

Water, sand and chemicals are injected into the rock at high pressure which allows the gas to flow out to the head of the well.

The process can be carried out vertically or, more commonly, by drilling horizontally to the rock layer, which can create new pathways to release gas or used to extend existing channels.

The term fracking refers to how the rock is fractured apart by the high-pressure mixture.

Drilling for shale gas is still at an exploratory phase.

However, reserves of shale gas have been identified across large swathes of the UK, particularly in northern England.

More than 100 licences have been awarded by the government, allowing firms to pursue a range of oil and gas exploration activities in certain areas.

Before companies can begin fracking they must also receive planning permission from the relevant local council.

Cuadrilla faced legal challenges before it could begin drilling at its Preston New Road site at Little Plumpton in Lancashire.